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1-6 Understanding the PCM30 line drawer
297-2101-504 Standard 02.01 December 1991
How the PCM30 line drawer is configured
Figure 1-4 illustrates the physical configuration of the PLD. The PLD is
physically similar to the standard line drawer and includes the following
components:
•
bus interface card
•
PCM30 interface card
The PLD connects to the digital distribution frame by four coaxial cables,
which terminate on the rear of the drawer.
Within the PLD are two subgroups or logical drawers, and each subgroup or
logical drawer supports one PCM30 link within time slots 1 to 15 and 17 to
31. The time slots of the logical PLD are mapped one-to-one onto the line
equipment number of the logical standard line drawer. Slots 0 and 16 are not
used.
Within the PLD, the upper part of the drawer is the even-numbered
subgroup and the lower part is the odd-numbered subgroup. Within the
standard line drawer, however, the upper part of the drawer is the
odd-numbered subgroup and the lower part is the even-numbered subgroup.
The bus interface card is located at the front of the drawer directly behind
the faceplate. It monitors drawer activity and provides an interface between
the two 30-channel subgroups and the digroup control card.
The PCM30 interface card is located behind the bus interface card and
occupies slot numbers 5 and 21. It provides two PCM30 interfaces at 2
Mbps to the customer terminating equipment and interfaces with the bus
interface card by means of a DS60 serial link at 5.12 Mbps.